Pipe coupling

ABSTRACT

The invention provides a pipe coupling (2) for connecting together a first pipe member (P1) having a liner pipe (L1) arranged in the bore thereof, to a second pipe member (P2); the pipe coupling comprising a first sleeve member (8) arranged to receive an end of the first pipe member (P1) whereby an end of the liner pipe (L1) can protrude axially therefrom; a second sleeve member (10) arranged to receive an end of the second pipe member (P2); a first annular sealing means (12) for disposal about the first pipe member (P1), the first annular sealing means (12) being arranged axially between a first annular collar (4) and the first sleeve member (8); second annular sealing means (14) and first gripping means (62) for disposal about an end of the liner pipe (l1), the second annular sealing means (14) being arranged axially between the first and second sleeve members (8,10); third annular sealing means (16) for disposal about the second pipe element (P2), the third annular sealing means (16) being arranged axially between a second annular collar (6) and the second annular sleeve member (10); and means (34,36,38) for drawing the first and second annular collars (4,6) axially together such that the first annular sealing means (12) is compressed axially between the first annular collar (4) and the first sleeve member (8) and is deformed radially inwardly to seal against the first pipe member (P1); the second annular sealing member (14) and first annular gripping means (62) are compressed axially between the first and second sleeve members (8,10) such that the second annular sealing member (14) is deformed radially inwardly into sealing contact with the end of the liner pipe (L1) and the first annular gripping member (62) is urged radially inwardly into gripping contact with the liner pipe (L1); and the third annular sealing member (16) is compressed axially between the second annular collar (6) and the second sleeve member (10) and is deformed radially inwardly into sealing contact with the second pipe member (P2).

BACKGROUND OF THE INVENTION

This invention relates to a pipe coupling for coupling together a pipehaving a liner pipe, hose or sleeve disposed therein to a second pipemember.

Until recently, pipes made from ferrous materials have been used forpipelines, and in particular mains pipelines, for conveying servicessuch as gas and water. A substantial problem with such ferrous pipes hasbeen their tendency to corrode over a period of several years' useleading to loss of integrity of the pipe wall. One solution to thisproblem has to been to provide a liner pipe, hose or sleeve formed froma suitable material, for example a plastics material such aspolyethylene, or an elastomeric material. In order to undertake a pipelining operation, it is necessary to dig a trench at either end of theferrous pipe section to be repaired, the liner being pulled through thehost pipe bore such that eventually its end protrudes beyond the ferrouspipe end. In order to ensure that the joint is fluid tight, it is thennecessary to provide a mechanical seal between the pressure-containingplastics liner and the pipe or fitting to which it is connected, and itis also necessary to provide a mechanical seal between the plasticsliner pipe and the host pipe against the ingress of ground water, and agripping means for preventing retraction of the liner pipe into the hostpipe.

It is an object of the present invention to provide such a pipecoupling.

SUMMARY OF THE INVENTION

Accordingly, in a first aspect, the invention provides a pipe couplingfor connecting together a first pipe member having a liner pipe arrangedin the bore thereof, to a second pipe member; the pipe couplingcomprising a first sleeve member arranged to receive an end of the firstpipe member whereby an end of the liner pipe can protrude axiallytherefrom; a second sleeve member arranged to receive an end of thesecond pipe member; a first annular collar disposed axially outwardly ofthe first sleeve member and being arranged in use to encircle the firstpipe member; a second annular collar disposed axially outwardly of thesecond sleeve member and arranged in use to encircle an end of thesecond pipe member; a first annular sealing means for disposal about thefirst pipe member, the first annular sealing means being arrangedaxially between the first annular collar and the first sleeve member;second annular sealing means and first gripping means for disposal aboutan end of the liner pipe, the second annular sealing means beingarranged axially between the first and second sleeve members; thirdannular sealing means for disposal about the second pipe element, thethird annular sealing means being arranged axially between the secondannular collar and the second annular sleeve member; and means fordrawing the first and second annular collars axially together such thatthe first annular sealing means is compressed axially between the firstannular collar and the first sleeve member and is deformed radiallyinwardly to seal against the first pipe member; the second annularsealing member and first annular gripping means are compressed axiallybetween the first and second sleeve members such that the second annularsealing member is deformed radially inwardly into sealing contact withthe end of the liner pipe and the first annular gripping member is urgedradially inwardly into gripping contact with the liner pipe; and thethird annular sealing member is compressed axially between the secondannular collar and the second sleeve member and is deformed radiallyinwardly into sealing contact with the second pipe member.

The term pipe member as used herein refers to pipes as such, and also topipe-like members such as elbows, bends, T-pieces, adaptors, valvebodies, and like members. The term liner pipe as used herein includesliner hoses and liner sleeves as well as liner pipes.

The first pipe member is typically a ferrous pipe member, for example acast iron mains pipe.

The second pipe member can be formed from any pipeline material, buttypically is formed from a ferrous material such as ductile iron orsteel, or a plastics material such as a polyolefin or a polyvinylhalidematerial (e.g. polyvinylchloride).

The liner pipe is usually formed from a suitable plastics material suchas a polyolefin, e.g. polyethylene. Typically, the liner pipe will havea supporting element, for example a support sleeve, disposed in the endthereof to prevent the liner from collapsing radially inwardly whencompressed.

The first and second annular collars are preferably provided withradially extending flanges having an array of aligned holes throughwhich flange bolts can be positioned, tightening of the flange boltsserving to draw the collars axially together.

Alternatively, the annular collar(s) can be threaded to engagecomplementary threads on the respective sleeve members.

The first and second sleeve members typically have radially outwardlyinclined (i.e. flared) end portions at their axial outer ends. In use,the first and third annular sealing members are urged against therespective flared end portions as the annular collars are drawntogether, the inclined surfaces of the flared portions assisting thesealing members to be deformed radially inwardly against the respectivepipe members.

The axially inner ends of the first and second sleeve members can beconfigured so that together they define an annular cavity within whichis disposed the second sealing member and the first annular grippingmember. One of the sleeve members can have an axially inner end(hereinafter referred to as the spigot portion) which is radiallyoutwardly inclined (i.e. flared) and is of a size enabling it to bereceived within a socket portion of the axially inner end of the othersleeve member. The socket portion can comprise a generally cylindricalor slightly inclined region extending in a direction towards the axiallyouter end of the sleeve member into a radially inwardly inclined (i.e.tapering) abutment surface. The inner surface of the spigot portion, andthe generally cylindrical or slightly inclined region and taperingabutment surface of the socket portion together can define the annularcavity.

The annular cavity can contain only an annular sealing means, butpreferably the cavity also contains the first annular gripping means forgripping the liner pipe. The first annular gripping means can be formedintegrally with the sealing means or it can be a separate element. Forexample, the gripping means can take the form of gripping elementsembedded in the sealing means.

In a further aspect, the invention provides a pipe joint comprisingfirst and second pipe members and a liner pipe disposed within the firstpipe member; the first and second pipe members and liner member beingcoupled together by means of a pipe coupling as hereinbefore defined.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 which is a partial sectional elevation through a pipe couplingaccording to one embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, the coupling 2 comprises first and secondannular collars 4, 6, first and second sleeve members 8, 10, and first,second and third annular sealing members 12, 14, 16.

First sleeve member 8 is generally cylindrical in form and is typicallyfabricated from ductile or malleable iron, or mild steel. Sleeve member8 has a flared axial end portion 18 and a radially inwardly orientedabutment portion 20. Abutment portion 20 has an axially outer surface20a which is generally perpendicular to the axis of the coupling. Theaxially inner surface 20b of the abutment portion is inclined and formsa tapering abutment surface.

The second sleeve member 10 has an enlarged bore portion 22 and areduced bore portion 24, the enlarged and reduced bore portions 22, 24being linked by a radially inclined portion 26. Both the reduced boreportion and the enlarged bore portion extend into radially outwardlyflared portions 28, 30 respectively.

At either end of the coupling are annular collars 4 and 6. In thisembodiment, the annular collars are substantially identical in form,each having an array of aligned holes 32, 33 through which a flange bolt34 is inserted. A nut 38 engages the threaded region 36 of the flangebolt enabling the two annular collars to be tightened together.

Each of the annular collars 4, 6 have annular lip portions 40, 42 attheir radially inner edges.

Disposed axially between the first annular collar 4 and the first sleevemember 8 is the first annular sealing member 12. Annular sealing member12 has a generally cylindrical radially inner surface 44 configured toprovide a plurality of annular gripping ribs 46. The sealing member 12has a radially outwardly inclined surface 48 and an annular recessregion 50. In use, the axially inner end of inclined surface 48 abutsagainst the flared portion 18 of the sealing member 8.

The annular collar 4, sealing member 12 and sleeve member 8 are shapedso as to be able to receive therein an end of a mains pipe P1, which maybe for example a cast iron mains pipe. Mains pipe P1 has extending fromthe end thereof a link of liner pipe L1 which is formed from a suitablegrade of polyethylene. Disposed within the protruding end of the linerpipe L1 is a short length of a reinforcing liner R which may, forexample, be formed from a plastics material such as polyethylene or ametal such as aluminium.

The sleeve member 8 has, at its axially inner end, a socket portion 9defined by a generally cylindrical but slightly tapering region 9a andthe tapering abutment surface 20b. The generally cylindrical region 9aand the abutment surface 20b, together with the inner surface of theflared end 28 of the second sleeve member 10, form an annular cavity 60within which are disposed the second annular sealing member 14 and agripping member 62. Second annular sealing member 14 has a generallycylindrical radially inner surface provided with an array of annularribs 61, and has a radially inclined surface 64 at its axially innerend. The radially inclined surface 64 rests against the radially innersurface of the flared portion 28 of the second sleeve member 10.Gripping member 62 typically is formed from a plastics material, e.g. anengineering plastics material such as Nylon or polyacetal, although itcould be made instead from a metal such as steel, and has an array ofannular gripping ribs or serrations 64 on its radially inner surface.Gripping ring 62 also has a radially inclined surface 66 which abutsagainst inclined surface 20b of the abutment portion 20 of the firstsleeve member 8.

Disposed between the second sleeve member 10 and the second annularcollar 6 is the third annular sealing member 16. As with the first andsecond annular sealing members, the third annular sealing member has anarray of ribs 70 on its radially inner surface, and has a radiallyinclined surface 72 which abuts against the radially inner surface ofthe flared end portion 30 of the second sleeve member.

The second annular collar 6, the third sealing member 16 and theenlarged bore portion 22 of the second sleeve member are configured toreceive therein an end of a second pipe member P2 which may be, forexample, a short length of polyethylene or metal pipe.

In use, the first and second pipe members P1 and P2 are inserted intothe respective ends of the coupling, such that the liner pipe L1protrudes from the end of the mains pipe P1, and the two annular collars14 and 16 are drawn axially together by tightening the flange bolt/nutarrangements 34, 36, 38 as the two annular collars 14, 16 are drawntogether, each of the annular sealing members are compressed anddeformed radially inwardly into contact with their respective pipemembers or liner pipe.

Thus, first annular sealing member 12 is compressed axially between theflared end portion 18 of the first sleeve member 8 and an axially innerface 4a of the first annular collar 4. As the inclined surface 48 of thesealing member 12 is urged into engagement with the radially innersurface of flared portion 18, the effect is to compress the sealingmember 12 radially inwardly against the mains pipe P1, thereby to form aseal between the mains pipe P1 and the sleeve member 8. The resultingseal prevents, for example, entry of ground water into any annular spacebetween the pipe P1 and the liner pipe L1.

As the annular collars 4 and 6 are drawn together, the second sealingmember 14 and the gripping member 62 are compressed between the firstand second sealing members and are urged radially inwardly into sealingand gripping contact with the liner pipe L1. The gripping ribs orserrations 66 of the gripping member bite into the outer surface of theliner to prevent it from being dislodged, whilst the sealing memberprovides a seal between the first sleeve member 8 and the liner pipe L1and also between the second sleeve member 10 and the liner pipe L1. Thesupport sleeve R disposed within the end of the liner prevents the linerfrom collapsing as it is subjected to compressive forces.

A seal is formed in similar fashion between the second pipe member P2and the sleeve member 10 by means of compression of the third annularsealing member 16. In this case, the third sealing member is compressedbetween an inner axially inner face 6a of the annular collar and theradially inner surface of the flared portion 30 of the second sleevemember 10.

The arrangement shown in FIG. 1 has certain advantageous properties.Thus for example, it is easy to install and can be used to connecttogether pipes formed from a variety of different types of material andhaving different diameters. In particular, it can be used on essentiallyany type of pipe material P2 and can accommodate different lengths ofpipe P2 to suit different trench conditions.

The invention has been illustrated by reference to a single embodimentas shown in FIG. 1, but it will readily be appreciated that numerousmodifications and alterations could be made to the embodiment shown inFIG. 1 without departing from the principles underlying the invention.All such modifications and alterations are intended to be embraced bythis application.

I claim:
 1. A pipe coupling for connecting together a first pipe memberhaving a liner pipe arranged in the bore thereof, to a second pipemember; the pipe coupling comprising a first sleeve member arranged toreceive an end of the first pipe member whereby an end of the liner pipeprotudes axially therefrom; a second sleeve member arranged to receivean end of the second pipe member; a first annular collar disposedaxially outwardly of the first sleeve member and being arranged in useto encircle the first pipe member; a second annular collar disposedaxially outwardly of the second sleeve member and arranged in use toencircle an end of the second pipe member; a first annular sealing meansfor disposal about the first pipe member, the first annular sealingmeans being arranged axially between the first annular collar and thefirst sleeve member; second annular sealing means and first grippingmeans for disposal about an end of the liner pipe, the second annularsealing means being arranged axially between the first and second sleevemembers; third annular sealing means for disposal about the second pipeelement, the third annular sealing means being arranged axially betweenthe second annular collar and the second annular sleeve member; andmeans for drawing the first and second annular collars axially togethersuch that the first annular sealing means is compressed axially betweenthe first annular collar and the first sleeve member and is deformedradially inwardly to seal against the first pipe member; the secondannular sealing member and first annular gripping means are compressedaxially between the first and second sleeve members such that the secondannular sealing member is deformed radially inwardly into sealingcontact with the end of the liner pipe and the first annular grippingmember is urged radially inwardly into gripping contact with the linerpipe; and the third annular sealing member is compressed axially betweenthe second annular collar and the second sleeve member and is deformedradially inwardly into sealing contact with the second pipe member.
 2. Apipe coupling according to claim 1 wherein said means for drawingincludes the first and second annular collars provided with radiallyextending flanges having an array of aligned holes through which flangebolts can be positioned, tightening of the flange bolts serving to drawthe collars axially together.
 3. A pipe coupling according to claim 1wherein the first and second sleeve members have radially outwardlyinclined end portions at their axial outer ends.
 4. A pipe couplingaccording to claim 1 wherein the axially inner ends of the first andsecond sleeve members are configured so that together they define anannular cavity within which is disposed the second sealing member andthe first annular gripping member.
 5. A pipe coupling according to claim4 wherein the annular cavity contains only the second annular sealingmeans.
 6. A pipe coupling according to claim 4 wherein the annularcavity contains the second annular sealing means and the first annulargripping means for gripping the liner pipe.
 7. A pipe coupling accordingto claim 4 wherein one of the sleeve members has an axially inner endforming a spigot portion which is radially outwardly inclined and is ofa size enabling it to be received within a socket portion of the axiallyinner end of the other sleeve member.
 8. A pipe coupling according toclaim 7 wherein the socket portion comprises a generally cylindrical orslightly inclined region extending in a direction towards the axiallyouter end of the sleeve member into a radially inwardly inclinedabutment surface.
 9. A pipe coupling according to claim 8 wherein theinner surface of the spigot portion, and the generally cylindrical orslightly inclined region and tapering abutment surface of the socketportion together define the annular cavity.
 10. A pipe couplingaccording to claim 1 wherein the first annular gripping means and thesecond annular sealing means are defined by a single member.
 11. A pipecoupling according to claim 1 wherein the first annular gripping meansand the second annular sealing means are defined by separate members.12. A pipe coupling according to claim 1 wherein the first annulargripping means and the second annular sealing means are formedintegrally.
 13. A pipe coupling according to claim 12 wherein the firstannular gripping means takes the form of gripping elements embedded inthe second annular sealing means.
 14. A pipe joint comprising a firstpipe member having a liner pipe arranged in the bore thereof, a secondpipe member; and a pipe coupling; the pipe coupling comprising a firstsleeve member having received therein an end of the first pipe memberwhereby an end of the liner pipe protrudes axially therefrom; a secondsleeve member having received therein an end of the second pipe member;a first annular collar disposed axially outwardly of the first sleevemember and encircling the first pipe member; a second annular collardisposed axially outwardly of the second sleeve member and encircling anend of the second pipe member; a first annular sealing means disposedabout the first pipe member, the first annular sealing means beingarranged axially between the first annular collar and the first sleevemember; second annular sealing means and first gripping means disposedabout an end of the liner pipe, the second annular sealing means beingarranged axially between the first and second sleeve members; thirdannular sealing means disposed about the second pipe element, the thirdannular sealing means being arranged axially between the second annularcollar and the second annular sleeve member; and means for drawing thefirst and second annular collars axially together such that the firstannular sealing means is compressed axially between the first annularcollar and the first sleeve member and is deformed radially inwardly toseal against the first pipe member; the second annular sealing memberand first annular gripping means are compressed axially between thefirst and second sleeve members such that the second annular sealingmember is deformed radially inwardly into sealing contact with the endof the liner pipe and the first annular gripping member is urgedradially inwardly into gripping contact with the liner pipe; and thethird annular sealing member is compressed axially between the secondannular collar and the second sleeve member and is deformed radiallyinwardly into sealing contact with the second pipe member.
 15. A pipejoint according to claim 14 wherein said means for drawing includes thefirst and second annular collars provided with radially extendingflanges having an array of aligned holes through which flange bolts canbe positioned, tightening of the flange bolts serving to draw thecollars axially together.
 16. A pipe joint according to claim 14 whereinthe first and second sleeve members have radially outwardly inclined endportions at their axial outer ends.
 17. A pipe joint according to claim14 wherein the axially inner ends of the first and second sleeve membersare configured so that together they define an annular cavity withinwhich is disposed the second sealing member and the first annulargripping member.
 18. A pipe joint according to claim 17 wherein one ofthe sleeve members has an axially inner end which is radially outwardlyinclined and is of a size enabling it to be received within a socketportion of the axially inner end of the other sleeve member.
 19. A pipejoint according to claim 17 wherein the annular cavity contains thesecond annular sealing means and the first annular gripping means forgripping the liner pipe.
 20. A pipe coupling according to claim 14wherein the first annular gripping means and the second annular sealingmeans are defined by separate members.